4x4 Transmission Options For 350 Crate Motor Swap?

Hello,

I have a 1968 Jeep CJ-5 with the 225 V-6. I’m thinking of doing a Chevy 350 swap with but I don’t know a whole lot when it comes to transmissions. I want to keep it 4x4 but I have no idea what the best options are for transmissions. Does anyone have some suggestions?

Any help is appreciated.

Thanks in advance.

 

That's a loaded question.
What do you want to do with the jeep?
Do you need low gears for off road 4x4 adventures?
While I realize that a v8 powered jeep puts a smile on a mans face, it really wont do much more than a v6. What's wrong with your v6?

 

Novak Conversions Transmission Knowledge Gateway (novak-adapt.com)

 

V8 in a pre 72 is not really worth the effort if you already have the Dauntless. Just my opinion.
As for the tranny; 4 speed with a granny gear would be my choice, SM420 or SM465. Both bolt to a GM bellhousing.

 

I would agree with the above. The 225 also responds well to a few minor upgrades-manifold/carb/headers/cam. IMO, more power than its 1972 replacements. And a 68 should have the T14 transmission, a significant improvement on either the T90 or T86AA. Is the Jeep currently running? With the optional 4.89 gears and an overdrive, it makes a decent off road rig as is and is capable of keeping up with modern traffic.

And welcome aboard the best Jeep site.

 

I'll pile on with everyone else. I have a '69 with a Dauntless and a '71 with a Buick 350. If the V8 wasn't already in the '71 when I got it I would never convert to it. The Dauntless is a great motor.

 

I should also note getting a decent radiator/fan/shroud in a short-nosed V8 Jeep can be a challenge. I had to redesign all that on mine because it overheated at low speeds when I got it.

 

I'ld just do a 4.3l v6 1990 is best
It's a good fairly common, affordable package for a short nose cj and with some pistons and a cam it will move

 

A Chevy engine will bolt up to your 3 speed, but it really isn't strong enough for V8 power. Best bet would be a Chevy truck 4 speed, either SM 420 or SM 465. If you don't need the low 1st gear, you could use a T15 3 speed, but they're not easy to find these days.
Good info about 4 speed swaps here-
Truck 4-speed Transmissions As I Understand Them | ECJ5 (earlycj5.com)

 

An old-school transmission conversion is a passenger car 4 speed (T10, Muncie M20, Iron Saginaw) with an AA or Novak adapter to the D18. It all depends on how you intend on using it.
As mentioned earlier, a V8 is not the best choice due to the short engine compartment, and the torque of a 350 is overkill for a small Jeep. Do you plan on stonger axles too? The 283 and 327 are much better suited if you insist on a V8.
A 4.3 V6 is a much better choice, and why swap out the 225? The Dauntless is a great engine in the early 81" CJs and is more than adequate for power, plus it has a very unique sound. Just because you have a 350 doesn't make it a good choice for an early Jeep.
-Donny

 

The Jeep is mostly for cruising around. It will most likely be on the road far more than it will be off road. The granny gear may not really be needed but I would like to keep it 4x4. Side note: At the moment I take my truck when I travel and do some off road with it adventures with it. That may change once the Jeep is up and running and if I attach a tow bar or something.

 

Thanks for the link. Great resource.

 

Is it not worth it because the current V6 is a great engine? Or is it not worth it for some other reason?

 

Do you know if there is a resource that goes over the best upgrades and mods for that engine? No, the Jeep is not running. When I bought it, it was running but I found that it had a bad fuel pump and a large hole in the rusted gas tank. I installed the new fuel pump and bought a new tank from Willys Jeep Parts | Kaiser Willys Jeep Parts and Restoration. When I went to install the new tank I noticed that my old tank had a return line and the new tank does not. Also, the fuel line fittings do not match the new tank. When I asked Mike over at Kaiser Willys, he said that model does not have a return line and someone must have modified the tank. So at the moment I am trying to size the threads on the tank so I can gett the line hooked up. Not really sure what to do with the return line since the fuel pump also has it.

 

I did notice that when looking at the engine bay. Seemed to be pretty small area.

 

From a driving perspective, a 350 isn't going to do anything a 225 won't, except be more likely to break drivetrain components. The 4.3 V6 is a great swap, and actually gives you some less expensive (or at least more easily adaptable) transmission options, due to it sharing the standard small block chevy bellhousing pattern. But I personally wouldn't say it's *better* than the 225, Just different, and a bit more "modern" of an engine, as you can easily find them with EFI from the factory, and it's not *that* hard to swap the whole works over.

 

A V8 will fit, but not easily. Lots of Chevy V8s have gone into these Jeeps. The newer ('72 up) core support might help, since it dispenses with most of the tunnel in front of the engine. Or you can recess the firewall to clear the distributor. Front mounted distributor on the Buick is an advantage that way.

Back in the day, the 225 V6 was newly available and picked because it fit. The design was discarded by GM, who later bought the rights back and would use in its compact cars after AMC took over Jeep. The V6 configuration is popular today in passenger cars, and several likely swap candidates exist. The 4.3L Chevy V6 is a very popular upgrade for a Jeep that does not already have the 225. The 4.3L with native EFI is much more available today than the 225, though swapping for the 225 seems like a sideways move.

 

The current engine is a great engine for the purpose (Jeeping), on and off road.


I believe the under seat gas tank had different versions, that maybe why you’re having a mismatch.

In my opinion this is the best sight for your research. This sight is best searched using your normal search engine (Google, Bing, …..).
Search ‘earlycj5.com’ followed by your search request.
i.e. ‘earlycj5.com 225 upgrade’ or ‘earlycj5.com 4 speed swap’

There is a lot of info in the previously posted threads here.

 

I forgot to mention that my suggestion would be to get the Jeep running safely using the drivetrain you have. Drive it and use it. Find out what you don’t like and what you do. On these early CJ’s I would upgrade the brakes and/or steering before you pull a running 225 for a 350 swap IMO. I have a 71 with the 225, T14 3 speed, 4.88 gears and over drive. I am not changing any of it.